The present invention relates in general to apparatus and methods for protocol conversion between telephony systems, such as advanced intelligent networks, having incompatible telephony signaling protocols. In particular, the present invention relates to a configurable, universal signaling protocol converter, a system or network having such a protocol converter and a method of protocol conversion that enables communication between signaling protocols of two or more pieces of telephony equipment.
In the past decade, the pace of deregulation of the telecommunications markets around the world has accelerated rapidly. Federal telecommunications liberalization legislation in the United States, the European Community""s mandate that its member nations liberalize their telecommunications markets by January 1998, and the World Trade Commission""s agreement on freeing trade in telecommunication""s markets world wide have combined to result in a period of unprecedented growth in the global telecommunications market. New carriers are being created to compete against the old monopolies, established monopolies and carriers are merging and forming joint ventures to create global giants, and fringe market players (resellers and call back operators) are expanding their product lines and extending into new markets.
As carriers build new networks and extend existing networks to new markets, they are encountering many technological challenges which they did not face when they operated only in a single, domestic, market. One of the most significant challenges is that of managing the myriad of communications network protocols which are used in different markets. Telecom operators must interface with a variety of customer Private Branch eXchange (PBX) equipment, and must also interconnect with other operators for access and egress. Today, there are between 35 to 50 variants of base protocols. The ability of the new entrants to support customer access, local, long distance and international protocols often determines their ability to compete successfully.
Communications protocols are the xe2x80x9clanguagesxe2x80x9d that allow telecommunication equipment (switches, routers, customer premise equipment, etc.) to communicate with each other. It is essential for a new carrier to be able to support the protocols of its customers, to provide access for their existing Customer Premises Equipment (CPE), and the other networks with which it must interconnect, via switch to switch interconnections. Moreover, the creation of more advanced services, such as Intelligent Networking, requires that communication""s protocols contain increasingly detailed information and the migration towards ATM (Asynchronous Transfer Method) network backbones requires the capability to support voice network protocols through data networks.
The technical solutions to this problem, that are available today, have not sufficiently met the requirements of the network operators. Traditionally, network service providers have supported protocols directly on the network switches. This was an adequate solution when the carriers operated only in a single market, but as they expand, their switches do not support the new protocols and the development time and cost for adding all required protocols to their switches are prohibitive. Voice protocol conversion solutions available in the past have been managed on a one-to-one basis which result in small, hardware based solutions. These solutions are inflexible, have limited scalability, are unstable, and do not operate as truly integrated parts of the carrier""s network.
One example of the problems with the prior art is in a connection between a protocol used by Deutsche Telekom AG and another protocol, such as G1. When a party using the protocol of Deutsche Telekom AG generated a call signal and the other protocol generated a busy signal, the Deutsche Telekom AG threw away the busy signal and continued to generate the ring signal to the calling party. Rather than change their protocol, Deutsche Telekom AG used a mechanical solution of monitoring the tone.
Another example of a problem with conventional equipment arises when large multinational corporations use a first protocol, such as DPNSS, to provide a xe2x80x9ccall holdxe2x80x9d between the company""s PBX""s using leased trunk lines. However, these trunks cannot be extended across national boundaries due to high expense, national regulations, and incompatible service providers. The telecom service provider used by the company determines that each country supports a similar, but not exact, Integrated Services Digital Network (ISDN) public facility signaling system. Both systems, for example, are compliant with ITU Q.931, but use two network-dependent fields in a different manner. The requirements for connectability then become:
1. Convert a DPNSS xe2x80x9ccall holdxe2x80x9d message sequence to an ISDN message sequence for Country A;
2. Convert ISDN messages in Country A format to ISDN messages in country B format; and
3. Convert ISDN messages in Country B format to DPNSS for deliver to the remote PBX.
Consequently, a convoluted, multi-conversion process must be implemented.
Accordingly, there exists a need for a universal, simplified, but easily configurable protocol converter which can be used by many different protocol systems; that can be easily configured for new protocols and changes to existing protocols. This need has existed for a long time and has not been solved by the existing equipment.
The present invention was developed to provide a solution to protocol conversion by providing customers with a flexible, any-to-any, protocol conversion platform which is integrated in the network as a network element. This product is unique in its market and provides telecommunications service providers with new capability to quickly, and in the field, adapt their networks to the needs of a new protocol which facilitates their ability to launch new products and extend into new markets and to compete in the rapidly changing global market environment.
Accordingly, the present invention provides an intelligent signaling protocol converter that, for example, can be used for multiple Common Channel (e.g. C7 or PRI) and Channel Associated Signaling (CAS) protocol conversions and that is designed to support voice to data protocol conversions in its next generation. The present invention is a true network element that is scalable, will operate in a fault environment, and provides interfaces to network management systems typically used in a telephone company central office environment. An advantage of the present invention is that it can be programmed by a customer through an interface that allows the user to build, map, alter and logically convert between multiple protocols. Thus, the present invention offers programmability, flexibility and a dynamic environment not currently provided by traditional protocol conversion alternatives. It eliminates the need for the traditional list of supported protocols commonly associated with switches and one-to-one protocol converters by providing a library of pre-defined protocols and it is relatively easy to add new protocols and protocol variations quickly.
The present invention provides advantages in network applications where it can be used to cost effectively expand a network and deliver central office functionality such as digit manipulation, billing and intelligent network interfaces close to the end user at significantly less cost than PBXs used as network switches. As such, a protocol converter according to the present invention can be paired with any tandem switch as traffic grows and switching becomes desirable. This enables system operators to support all current and future protocols, regardless of switch capability while freeing the switch from CPU-intensive conversion routines. This also eliminates long and costly development typically necessary to accommodate protocols and feature inter-working. As a remote access node, the protocol converter would be transparent to the bearer channel thus enabling only one leg of compression all the way from the customer site to the network switch.
The present invention has significant benefits for a carrier such as enabling rapid customer interconnection of any PBX and its associated access protocol, avoiding expensive and time consuming switch development to support new protocols, and facilitating the wider distribution of access nodes through cost effective and scalable implementations. The present invention maximizes the inter-working of supplementary features (e.g. a caller identification feature and a call forwarding feature), improves operational efficiency through remote access to real time date, provides continuous call state analysis, and permits rapid fault isolation. The invention facilitates the interconnection between networks, supporting network access and egress requirements, by sitting in-between the connecting switches to convert between the core network protocols used by each network. The software can be ported to equipment developed internally or by third party vendors to manage protocol conversion internal to existing or future network elements. The application software can be distributed among many platforms and storage media, or can reside on a single computer. Finally, the software""s design utilizing the universal call model facilitates the capability to map from voice protocols to data protocols to allow operators to migrate voice and data networks onto a single ATM backbone.
The present invention has significant benefits for a carrier such as enabling rapid customer interconnection of any PBX and its associated access protocol, avoiding expensive and time consuming switch development to support new protocols, and facilitating the wider distribution of access nodes through cost effective and scalable implementations. In addition, the present invention maximizes the inter-working of supplementary features (e.g. a caller identification feature and a call forwarding feature), improves operational efficiency through remote access to real time data, provides continuous call state analysis, and permits rapid fault isolation. Another advantage of the present invention is the elimination of decompression and recompression of the telephony signals at the access node thereby improving quality.
In one aspect of the present invention, a programmed general purpose digital computer receives signaling messages and logically converts the signals based on protocol definitions and customer-specified parameters into a non-protocol specific form (e.g. a generic protocol) and then converts the generic protocol into the requisite protocol of the receiving network. In this way, only one protocol converter is needed to service the expected protocols of an international telephony system, and this same converter, because it is receiving all of the incoming traffic, is capable of being used to provide valuable network usage data to generate network statistics and reports such as answer seizure ratio, call attempts, percentage failures and average holding time. In one specific environment where there is a conversion from a CAS or PRI protocol to a C7 protocol, the present invention can concentrate the signaling channels with the attendant advantages of eliminating the requirements for signaling terminals and the resulting need for costly switch expansion.
One specific embodiment of the present invention is directed to a universal protocol converter that converts the protocols of a first system to the protocols of a second system and that is comprised of an interface means for connecting with the first and with the second system; and a call instance for a call in which the call instance includes a means for converting the first protocol to a non-protocol specific representation, and then from this representation to the second protocol. This one embodiment can also include a generic state means for keeping track of the call by storing only data obtained from the non-protocol specific representations. It can also include a means for storing call context data of the generic protocol which is generated during the call, and it can include a means for manipulating the non-protocol specific representation when converting to the second protocol.
Another embodiment of the present invention is a telecommunications network that includes bearer channels and data channels and has first and second telecommunications systems having first and second protocols, respectively. The network also includes a means for converting between said first and second protocols that comprises a means for grooming the data on the data channels for data that both comes from the first and second telecommunications systems; means for converting the data to a non-protocol specific representation; means for temporarily storing the converted data; means for inter-working said temporarily stored data in accordance with a set of stored rules that depend upon the first protocol; means for converting the inter-worked data to conform with said second protocol; and means for reintroducing said converted data to said data channels of said second telecommunications system.
The present invention also includes a method by which a call control data stream of a request for bearer services is intercepted in transit between an originating communications node having a first protocol and a terminating communications node having a second protocol and is converted to a call control data stream of a terminating communications node. The method comprises intercepting the call control data stream that contains a plurality of information elements and transforming them into a non protocol specific form, storing the intercepted and transformed data elements; inter-working at least some of said stored data elements in accordance with predetermined rules; storing said inter-worked data elements; placing selected ones of said stored inter-worked data elements in the protocol of said terminating node; initiating an intermediate origination of a call control session; and using said data elements in the protocol of the termination node, by which such originally requested bearer services are obtained.
Generally speaking, the present invention is a software based, scalable, programable, means for interconnection of a plurality of heterogeneous network nodesxe2x80x94including, by way of example and not limitation, switching infrastructure, customer premises equipment, and intelligent network adjunct processorsxe2x80x94to enable the resulting combination to communication and interoperate with each other in providing network services and features that would not otherwise be within the individual or collective capabilities of such heterogenous network nodes.
Other features and advantages of the invention will be set forth in, or apparent from, the following detailed description of preferred embodiments of the invention.